Amid speculation this week over the goings-on inside the five star hotel-turned-detention centre in Riyadh where Saudi princes, business moguls and hybrids of the two are being detained is the mysterious case of Abdul Aziz bin Fahd.

A swirl of reports, tweets and even a dedicated hashtag have fuelled rumours that the youngest son of the late King Fahd was killed in a shootout while resisting arrest on Saturday or later in custody.

In an apparent attempt to quell rumours, the Saudi information ministry spokesman released a statement on Wednesday saying there was “no truth” to the reports of the 44-year-old’s death. “Prince Abdulaziz is alive and well,” the statement said.

The Ritz-Carlton in Riyadh (AFP)

A well-informed person told Middle East Eye that the prince has been under house arrest for a few months and was recently moved from Jeddah to the King Faisal Hospital, a 15-minute drive from the Ritz Carlton where his relatives are being held. The same person has said that the detainees will soon be released, to remain under house arrest until a trial scheduled to start on 1 December.

Still, like many of the reports coming out of Riyadh – including speculation that Lebanese Prime Minister Saad Hariri and Yemen President Abd Mansour Hadi are being held in the kingdom – it is impossible to confirm independently.

From future king to playboy

What is clear is that since his father’s death in 2005, the once-ascendant prince, who was raised to be a king, is now a minor figure in his family with little power – but a significant investment portfolio.

“He is the MBS that never made it,” said Madawi al-Rasheed, a visiting professor at the London School of Economics' Middle East Centre, referring to Crown Prince Mohammed bin Salman, Abdul Aziz's full cousin.

“He was groomed and spoiled and put in very senior positions when he was really like a teenager because [King] Fahd thought he could get away with this.”

Fahd’s strategy was typical of every other Saudi leader who has wanted to make his son king, Rasheed said. When the king, then in his eighties, appeared on TV or travelled, he would often take his young son along, even holding his hand.

Abdul Aziz bin Fahd helps carry his father's body out of the Imam Turki bin Abdullah mosque in Riyadh in August 2005 (AFP)

“He was apparently the favoured son and King Fahd doted on him quite heavily,” said Christian Henderson, an assistant professor of Middle East studies at the University of Leiden.

But the problem was timing: even as young Abdul Aziz was groomed for his role, his uncles were still young and energetic and unwilling to let King Fahd’s son succeed his father.

After his father died, the prince, then in his thirties, was deprived of his government posts and largely marginalised, living the life of a playboy typical of the younger generation of Saudi royals for some time.

“He’s been politically irrelevant for quite some time now. He’s this rather tragic figure that just kind of had a lot of money,” said Henderson.

Interests in Oger, MBC

And it's this money that has likely made him a target, say analysts. In light of the kingdom's oil-dependency and financial difficulties, Mohammed bin Salman has said one of the motivations behind the latest sweep has been to overhaul the system. The Wall Street Journal has reported that the crown prince is potentially eyeing $800bn in seized assets.

He oscillated from being the Don Juan then to sort of becoming very pious

- Madawi al-Rasheed, visiting professor at LSE's Middle East Centre

The prince's business interests range from major holdings in Saudi Oger – the construction company owned by the Hariri family that built up large swathes of the kingdom until it ran into financial troubles – to the Middle East Broadcasting Centre (MBC), whose head, Alwaleed al-Ibrahim, is thought to be one of the detained figures held at the Ritz Carlton. Al-Ibrahim is Abdul Aziz’s uncle on his mother's side, Henderson said.

The prince also reportedly invested in the Heron Tower in London and has a billion-dollar property portfolio in the US. In July 2013, he put a mansion in London’s Billionaires Row on sale for $131m.

One of the final episodes in the 2014 season of MBC's hit show, Arab Idol (AFP)

In 2014, gangsters carrying Kalashnikovs reportedly stole more than $262,000 from his 10-car convoy in “a movie-style heist” in France. The prince was apparently headed to a private jet at Le Bourget airport after spending almost two months in a luxury suite at the Four Seasons George V Hotel, owned by Prince Al-Waleed bin Talal, also thought to be held at the Ritz Carlton.

But in recent years, he appears to have had a spiritual awakening of sorts, said both Henderson and Rasheed.

“He oscillated from being the Don Juan then to sort of becoming very pious and citing Quranic verse and tweeting about them,” Rasheed said.

Earlier this year, Abdul Aziz’s tweets made headlines when he essentially defied his increasingly powerful cousin in public, defending Mohammed bin Nayef, the former crown prince removed from his post in June, and lashing out at the apparent partnership between Saudi Arabia and the UAE.